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  1. #include <stdio.h>
  2. #include <stdlib.h>
  3. #include <ctype.h>
  4. #include <string.h>
  5.  
  6. // delka [a-z] nebo [A-Z]
  7. #define ENG 26
  8. // delka [a-zA-Z]
  9. #define LEN_AlPHA 52
  10. // zacatecni delka 
  11. #define FIRST_LEN 10
  12. // funkce, ktera cte vstupni retezec
  13. char *read_line(int *line_length);
  14. //hledani delky posunu pri kodovani
  15. int search_shift(char*, char*);
  16. //desifrovani bez chyb
  17. int good_decoding(char*, int);
  18.  
  19. int main(int argc, char* argv[]) {
  20.  
  21. 	int i, shift = 0;
  22. 	int counter_code = 0, counter_decode = 0;
  23.     char *code, *bad_decode;
  24. 	int code_length, bad_decode_length;
  25.  
  26.     code = NULL, code_length = 0;
  27. 	bad_decode = NULL, bad_decode_length = 0;
  28.  
  29.     //cteni sifry
  30. 	code = read_line(&code_length);
  31. 	//pokud jsme nacetli sifru, tak muzeme nacist i spatny decode
  32. 	if ( code ) {
  33. 		bad_decode = read_line(&bad_decode_length);
  34. 	}
  35. 	//zjisteni delky sifry
  36. 	for (i = 0; i < strlen(code); i++) {
  37. 		counter_code += 1;
  38. 	}
  39. 	//zjisteni delky spatneho decodu
  40. 	for (i = 0; i < strlen(bad_decode); i++) {
  41. 		counter_decode += 1;
  42. 	}
  43. 	//pokud sifra obsahuje nespravne znaky
  44. 	for ( i = 0; i < counter_code; i++ ) {
  45. 		if ( isalpha(code[i]) == 0 ) {
  46. 			fprintf(stderr, "Error: Chybny vstup!\n");
  47. 			return 100;
  48. 		}
  49. 	}
  50. 	//pokud spatne desifrovani obsahuje nespravne znaky
  51. 	for ( i = 0; i < counter_decode; i++ ) {
  52. 		if ( isalpha(bad_decode[i]) == 0 ) {
  53. 			fprintf(stderr, "Error: Chybny vstup!\n");
  54. 			return 100;
  55. 		}
  56. 	}
  57. 	//pokud delky nejsou stejne
  58. 	if ( counter_code != counter_decode ) {
  59. 		fprintf(stderr, "Error: Chybna delka vstupu!\n");
  60. 		return 101;
  61. 	}
  62.     //pokud vsechno je v poradku
  63. 	shift = search_shift(code, bad_decode);
  64. 	good_decoding(code, shift);
  65. 	free(code);
  66. 	free(bad_decode);
  67. 	return 0;
  68. }
  69.  
  70. char *read_line(int *line_length) {
  71.  
  72.     int capacity = FIRST_LEN;
  73. 	char *line = malloc(capacity + 1);
  74. 	int length = 0;
  75.  
  76. 	if ( line == NULL ) {
  77. 		fprintf(stderr, "Error: Chybny vstup!\n");
  78. 	}
  79. 	else {
  80. 		int letter;
  81. 		while ( (letter = getchar()) != EOF && letter != '\n' ) {
  82. 			if (length == capacity) {
  83. 				char *line_v2 = realloc(line, capacity * 2);
  84. 				if ( line_v2 == NULL ) {
  85. 					free(line);
  86. 					line = NULL;
  87. 					length = 0;
  88. 					break;
  89. 				}
  90. 				capacity *= 2;
  91. 				line = line_v2;
  92. 			}
  93. 			line[length++] = letter;
  94. 		}
  95. 	}
  96. 	*line_length = length;
  97. 	return line;
  98. }
  99.  
  100. int search_shift(char *code, char *bad_decode) {
  101. 	int k, i, j;
  102. 	int counter = 0, minimum = 0, shift = 0;
  103.  
  104. 	for ( k = 0; k < LEN_AlPHA; k++ ) {
  105. 		for ( i = 0; i < strlen(code); i++ ) {
  106. 			if( code[i] == 'Z' ) {
  107. 				code[i] = 'z';
  108. 				code[i] = code[i] - ENG;
  109. 			}
  110. 			if ( code[i] == 'z' ) {
  111. 				code[i] = 'Z';
  112. 				code[i] = code[i] - ENG;
  113. 			}
  114. 			if ( (code[i] != 'Z') || (code[i] != 'z') ) {
  115. 				code[i]=code[i] + 1;
  116. 			}
  117. 		}
  118.  
  119. 		for( j = 0; j < strlen(code); j++ ) {
  120. 			if ( code[j] == bad_decode[j] ) {
  121. 				counter += 1;
  122. 			}
  123. 		}
  124. 		if ( counter > minimum ) {
  125. 			minimum = counter;
  126. 			shift = k + 1;
  127. 		}
  128. 		counter = 0;
  129. 	}
  130. 	return shift;
  131. }
  132.  
  133. int good_decoding (char* code, int shift) {
  134.     int k, b;
  135.     for ( k = 0; k < shift; k++ ) {
  136. 		for ( b = 0; b < strlen(code); b++ ) {
  137. 			if( code[b] == 'Z' ) {
  138. 				code[b] = 'z';
  139. 				code[b] = code[b] - ENG;
  140. 			}
  141. 				if ( code[b] == 'z' ) {
  142. 				code[b] = 'Z';
  143. 				code[b] = code[b] - ENG;
  144. 			}
  145. 			if ( (code[b] != 'Z') || (code[b] != 'z') ) {
  146. 				code[b]=code[b] + 1;
  147. 			}
  148. 		}
  149. 	}
  150. 	printf("%s\n", code);
  151.     return 0;
  152. }
  153.  
Success #stdin #stdout 0s 4368KB
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language:
C (gcc 8.3)
created:
3 years ago
visibility:
public

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